Muffling device



arch 9,' H937.

F. A. JIME-RSON 2,@73948@ MUFFL ING DEVICE Filed Oct. 4, 1934 N f @gk v BY RVEY

Patented Mar. 9, 1937 UNITED STES PATENT OFFICE MUFFLING DEVICE Application October 4, 1934, Serial No. '146,778

1 Claim.

This invention relates to muffling devices, and more particularly to an exhaust muiiiing device for fluid actuated motors.

One object of the invention is .to effectively suppress the sound waves induced by the emission of the fluid from the motor and to transform the exhaust impulses into a substantially steady stream.

Another object is to provide a simpliied and effective structure which will not add materially to the weight of the motor to which it is appended and which may be readily and cheaply replaced.

Other objects will be in part obvious and in part pointed out hereinafter.

In the drawing accompanying this specification and in which similar reference numerals refer to similar parts,

Figure l is a sectional elevation of a muffling device constructed in accordance with the practice of the invention and showing it applied to a uid actuated rotary motor, the latter being partly broken away, and

Figure 2 is a transverse View taken through Figure 1 on the line 2 2.

Referring more particularly to the drawing, the muiiling device designated, in general, by 20 is shown applied to a fluid actuated rotary tool 2| comprising a cylinder 22 and front and back heads 23 and 24 which may be secured to the cylinder in any suitable manner.

The cylinder 22 has a bore 25 to accommodate a liner 26 the interior of which constitutes a piston chamber 21 containing a rotor 28 having shaft portions 29 which extend into anti-friction bearings 30 in the cylinder and the back head. The rotor has a plurality of radial slots 3| in which are disposed vanes 32, and in one side of the liner are a series of inlet ports 33 which communicate with a supply passage 34 to admit pressure uid into the chamber 21' for operating the rotor 28. The exhaust uid passes from the chamber 21 through a series of exhaust ports 35 in the liner 26 and through a recess dened by the liner and the bore 25, to an exhaust port 31 in the wall of the cylinder 22.

The muiiiing device 29 is arranged on the exterior of the cylinder 22 adjacent the exhaust port 31. It is encased by a hollow extension 38 which may be an integral part of the cylinder and the interior of which constitutes an exhaust chamber 39. Overlyng the outer end of the chamber 39 is a plate 49 which seats against the extension 38 and is secured in position by a bolt 4l extending through the muliling device and threaded into a boss I8 on the outer surface of the cylinder 22. The plate 40 is of less width than the open end of the chamber 39 to define an exhaust port 45 through which the fluid issuing from the sheet 42 may pass to the atmosphere.

In the form of the invention illustrated, the muiiling device 2U consists of a sheet 42 of permeable material, as for example, felt. The sheet is preferably folded to U-shape of which the curved portion lies adjacent the wall of the cylinder and the legs lie on opposite sides of the bolt 4I and seat upon the plate 4D. The sheet extends from one side wall to the other of the chamber 39 and its upper edge seats against the boss and combines therewith and with the wall of the cylinder to deiine openings l9 on opposite sides of the boss for the passage of the major portion of the exhaust uid from the port 31 to the port 45.

A suitable container is provided for the sheet 42 in the form of a U-shaped plate 43 of which the curved portion and the legs lie exteriorly of the corresponding portions of the sheet. The container is preferably of the same length and height as the sheet 42 and has a series of perforations 44 through which exhaust uid may pass into and from the sheet 42.

In practice the present invention has been found to be a highly efficient device for suppressing the sound vibrations caused by the intermittent impulses of the exhaust uid issuing from the motor. Upon entering the chamber 39 the exhaust fluid is expanded and in passing through the chamber the impulses are evened out without causing any appreciable back pressure. The eX- haust fluid, therefore, finally passes through the exhaust port 45 as a substantially constant stream.

I claim:-

A muiler comprising a casing having an expansion chamber, said casing having an inlet opening and an outlet opening, a cover plate for one end of the casing and cooperating with the casing to define the outlet opening, a wall of permeable material extending from one side wall to the other of the casing between the openings and cooperating with the top of the casing to denne a passageway from the inlet opening to the outlet opening, and a bolt extending through the cover plate and the wall and being threaded into the casing to secure the cover plate and the wall rigidly to the casing.

FRANCIS A. JIMERSON. 

